14 results about "Magnetization curve" patented technology

This invention relates to a testing device for the magnetic properties of high-permeability materials under low-frequency weak magnetic environments, comprising: a coil assembly, a magnetic property tester, a magnetic shielding cylinder, and a host computer; the coil assembly is wound around the sample under test and connected to the magnetic property tester, and the sample under test with the coil assembly placed inside the magnetic shielding cylinder; the magnetic shielding cylinder provides a weak magnetic environment for the sample under test; the magnetic property tester is used to provide excitation current to the coil assembly and detect the induced voltage of the sample under test, and transmit the measured data to the host computer; the host computer is used to acquire the data measured by the magnetic property tester and plot the magnetization curve. The technical solution of this invention solves the problem that current magnetic property testing devices for magnetic materials cannot obtain the permeability of high-permeability materials under low-frequency weak magnetic environments, thereby improving the accuracy and precision of theoretical and simulation calculations of magnetic shielding devices and reducing the error between design and actual values.

The invention relates to the technical field of power transformer state monitoring, and discloses a transformer direct current magnetic bias current measuring method. According to the method, an initial characteristic model containing a magnetization curve inflection point and a winding resistance temperature coefficient is constructed based on a nameplate and historical data; when a transformer is in grid-connected operation, an exciting current transient waveform and a neutral point potential fluctuation sequence are synchronously captured, a direct current magnetic bias characteristic distortion component is separated from exciting current by using a model, and a neutral point potential trend term is decomposed to extract a direct current voltage residual error. And establishing a dynamic mapping relation between the two, and generating a direct current injection analog signal to be applied to the equivalent simulation loop. By calibrating the signal amplitude, the simulation and actual measurement exciting current characteristics reach a preset similarity, and finally, the calibrated steady-state amplitude is reversely converted into a primary side direct current magnetic bias current value. According to the method, the difficulty of direct measurement is avoided, and high-precision equivalent measurement of the direct-current magnetic bias current is realized through model analysis and simulation calibration.

This application provides a modeling method and system for predicting the core loss of a high-frequency transformer, comprising: measuring the magnetic properties of the core material at different frequencies based on an experimental platform, and obtaining the magnetization curve and loss density curve of the core material according to Ampere's circuital law; inputting the magnetization curve into a constructed geometric model, setting excitation and boundary conditions, establishing a finite element model and performing finite element simulation analysis to obtain the loss density distribution and magnetic flux density distribution within the high-frequency transformer core; and constructing a loss model by introducing a gradient coefficient and the average value of the loss density, the magnitude of the magnetic field strength gradient, and the average value of the magnitude of the magnetic field strength gradient obtained from the finite element model, to predict the core loss. This application provides important basis for material selection, geometric structure optimization, and thermal design of high-frequency transformers, helping to shorten the R&D cycle, reduce trial production costs, and improve the overall performance of high-frequency transformers.

The invention provides a three-dimensional rotating magnetic measurement device and a three-dimensional rotating magnetic measurement system, and relates to the technical field of magnetic measurement. The three-dimensional rotation magnetic measurement device comprises a base, a first rotation driving assembly, a second rotation driving assembly and a supporting rod, the first rotation driving assembly, the second rotation driving assembly and the supporting rod are arranged on the base, a sample base is arranged in the supporting rod and used for fixing a sample to be measured, and the sample base is in driving connection with the output end of the first rotation driving assembly. The supporting rod is in driving connection with the output end of the first rotating driving assembly to rotate around the first axis under driving of the first rotating driving assembly, the supporting rod is in driving connection with the output end of the second rotating driving assembly to rotate around the second axis under driving of the second rotating driving assembly, and the second axis is perpendicular to the first axis. The three-dimensional rotation magnetic measurement device can obtain the three-dimensional anisotropy information of the sample to be measured, is high in measurement efficiency and data reliability, and can construct a complete three-dimensional magnetization curved surface / ellipsoid.

The invention belongs to the technical field of measuring equipment, and particularly relates to a motor detection system and method for harbor machinery, and the system comprises a controller, a magnetic core, a magnetic field detection unit, and a bias magnetic field output unit. When the magnetic core is sleeved on the detected lead, the controller is configured to detect a magnetic field intensity change curve through the magnetic field detection unit; when the magnetic field intensity change curve is abnormal, the controller is further configured to drive the bias magnetic field output unit to output a corresponding bias magnetic field so as to adjust the magnetic field intensity change curve; the bias magnetic field output unit is arranged on the outer side of the magnetic core, so that the influence of an external magnetic field on the magnetic core magnetic conductivity can be restrained, namely the bias magnetic field is generated through the bias magnetic field output unit, a magnetic core working point is stabilized in a magnetization curve linear region, and therefore the influence of the external magnetic field on the magnetic core magnetic conductivity is eliminated; the magnetic field intensity change curve is accurately measured so as to truly reflect the insulation performance of the motor.

The invention discloses a manufacturing method of a magnetic response millimeter-scale adhesion mobile robot for intragastric targeted drug delivery and pathological detection and the adhesion mobile robot. The method comprises the following steps: manufacturing a magnetic sheet with a simple harmonic magnetization curve; manufacturing a flexible frame, wherein a plurality of mounting holes for accommodating magnetic sheets are formed in the flexible frame; each magnetic sheet with a simple harmonic magnetization curve is mounted to a flexible frame, thereby forming a magnetic response millimeter-scale adhesion mobile robot for intragastric targeted drug delivery and pathological detection. According to the adhesion mobile robot manufactured through the method, the thin liquid film is transmitted on the wet and slippery surface through wave type movement of the magnetic response sheet-shaped soft material, so that crawling propelling is achieved by means of counter-acting force generated by the liquid film, the robot can stably crawl on the wet and low-friction stomach tissue surface by means of the adhesion moving characteristic, and the robot has a good application prospect. Good environmental adaptability is shown.

This invention relates to the field of soft magnetic materials technology, and in particular to a Fe-Co-Al soft magnetic material, its preparation method, and its applications. The material is prepared from Fe, Co, and Al as raw materials, weighed according to an atomic ratio of Fe:Co:Al = 3:1:1, and then processed through melting, rapid cooling, and heat treatment to obtain a soft magnetic material with the chemical formula Fe₃CoAl. The resulting material has a fully ordered cubic crystal structure of type DO₃. At room temperature, it exhibits a saturation magnetization of 162 emu / g, a coercivity of approximately 28.5 Oe, and a steep initial magnetization curve, demonstrating excellent magnetization sensitivity and rapid response even under weak magnetic fields. The Fe₃CoAl soft magnetic material of this invention significantly improves permeability and reduces coercivity through the introduction of Co, and its preparation process is simple, has a short cycle time, and is suitable for industrial production.

The invention discloses a ferromagnetic material Isin model parameter inversion method and system based on hysteresis characteristics, and the method comprises the steps: obtaining an initial magnetization curve and a saturation hysteresis loop of a ferromagnetic material, and determining an experiment excitation magnetic field sequence; constructing a three-dimensional Isin model; inputting an excitation magnetic field sequence, calculating and generating a simulated initial magnetization curve and a saturated hysteresis loop by using a three-dimensional Isin model, and constructing a training data set containing a large number of sample pairs; constructing a parameter inversion neural network model, and performing supervised learning training on the neural network model by using the training data set; and inputting the experimental hysteresis characteristics into the trained parameter inversion neural network model, and outputting an optimal model parameter combination matched with the experimental hysteresis characteristics of the ferromagnetic material. According to the method, physical constraint is carried out on the Isin model by utilizing the hysteresis characteristic of a macroscopic experiment, inversion of relevant parameters of a microscopic magnetic domain structure in the model is realized, and a modeling basis is provided for further carrying out magnetic Barkhausen noise signal simulation and magnetic characteristic prediction.

The application discloses an imaging method based on magnetization curve fitting of magnetic particle relaxation time, comprising: generating a magnetic field free point (FFP); moving the FFP in a space range where a single magnetic nanoparticle-injected target object is located, generating a pulsed square wave excitation magnetic field at each FFP position, and receiving original signals generated by magnetic nanoparticles in the target object under excitation of the pulsed square wave excitation magnetic field; fitting a target magnetization curve by adjusting relaxation time related parameters in a preset double exponential decay function based on the original signals; taking an adjustment result of the corresponding relaxation time related parameters as a magnetic particle relaxation time detection result of the FFP position; and performing imaging based on at least one same item in the magnetic particle relaxation time detection results obtained based on all FFP positions to obtain a relaxation time imaging graph. The application can separately detect the relaxation time, and combines the FFP scanning to perform multi-color magnetic particle imaging to distinguish plaque, duct and blood vessel regions.

The application provides an error monitoring method, an electronic device, a system and a storage medium of a current transformer. The method comprises the following steps: collecting real-time voltage and real-time current of a secondary circuit of the current transformer, and determining magnetic induction intensity of the current transformer based on the real-time voltage; obtaining a magnetization curve of the current transformer, and determining magnetic field intensity of the current transformer based on the magnetic induction intensity and the magnetization curve; and determining real-time error of the current transformer based on the real-time current and the magnetic field intensity. The application can monitor the online error of the current transformer in real time without stopping the power supply of the current transformer and without the need of test personnel and test equipment to the site, solves the problem that the current transformer cannot be periodically checked due to the inability to stop the power supply, and thus avoids the loss of manpower and material resources caused by power-off detection.

The application provides a loss characteristic testing device and method of amorphous / nanocrystalline alloy core under complex working conditions, which is used for testing magnetic characteristics and loss characteristics under complex working conditions such as different stresses, temperatures, magnetic field frequencies and magnetic field strengths. The amorphous / nanocrystalline alloy core is very sensitive to stress, and stress is inevitably introduced in the processing process, interference assembly and actual use, which leads to the deterioration of loss performance. In addition, different working temperatures will change the loss performance of the amorphous / nanocrystalline alloy core. The current conventional testing method cannot obtain the influence degree and law of complex working conditions on the magnetic characteristics and loss characteristics of the amorphous / nanocrystalline alloy core. The device provided by the application comprises a high-low temperature box, a force applying device, a magnetic characteristic testing device and a special fixture for a sample, and can obtain the magnetic hysteresis loop, magnetization curve and loss curve of the amorphous / nanocrystalline alloy core sample when the stress and temperature change simultaneously. The device plays an important guiding significance for the design and application of the motor using the amorphous / nanocrystalline alloy core.

In the active half-bridge equalizer based on phase-shifted + direct current flow control, the output voltage of the half-bridge converter contains a direct current component, which causes the transformer core magnetization curve to operate asymmetrically, and in a severe case, the transformer core magnetic saturation will cause the equalizer to not operate normally. Therefore, the application discloses a transformer core anti-saturation algorithm based on a phase-shifted + direct current flow control equalizer, estimates the maximum magnetic induction intensity of the transformer core according to circuit operation parameters, determines whether to change the duty cycle of each half-bridge converter according to whether the maximum magnetic induction intensity is within a reasonable range, and re-estimates the maximum magnetic induction intensity until a reasonable range is reached. The application solves the adverse conditions caused by the transformer core saturation operation in the active half-bridge equalizer based on phase-shifted + direct current flow control, and ensures the safe operation of the active half-bridge equalizer based on phase-shifted + direct current flow control.

The application discloses a double-E type variable inductance design method based on a coupling index, which comprises the following steps: 1) performing magnetic coupling analysis on the coupling problem of the main winding and the control winding of the double-E type variable inductance, and defining a coupling index reflecting the coupling degree of the double-E type variable inductance according to the analysis result; 2) designing the main winding turns according to the maximum alternating current magnetic flux density and the maximum inductance value of the double-E type variable inductance and in combination with the coupling index; 3) establishing an improved Brauer magnetization curve model, improving the accuracy of the knee point of the Brauer magnetization curve model by adopting a segmented function, determining the relationship between the minimum equivalent permeability and the maximum magnetic field strength, and designing the control winding turns in combination with the minimum inductance value; and 4) evaluating the coupling degree of the design result according to the coupling index, ensuring that the coupling degree is within an acceptable range, and completing the double-E type variable inductance design. The application solves the problem that the existing design method does not consider the winding coupling problem of the variable inductance in actual application.

The present application belongs to the field of magnetic particle biomedical detection and imaging, and particularly relates to a magnetic particle relaxation time detection method based on pulsed square wave excitation and curve fitting, aiming at solving the problem that the prior art cannot effectively distinguish and detect the NMR relaxation time and Brownian relaxation time of magnetic nanoparticles. The method comprises: obtaining a sample signal generated by a magnetic nanoparticle sample under the excitation of a pulsed square wave excitation magnetic field; combining the sample signal, adjusting the relaxation time related parameters in the pre-constructed double exponential decay function and performing the fitting of the magnetization curve, and then obtaining a target magnetization curve matched with the sample signal; and taking the relaxation time related parameters corresponding to the target magnetization curve as the magnetic particle relaxation time detection result. The present application can effectively distinguish and detect the NMR relaxation time and Brownian relaxation time of magnetic nanoparticles, and can expand the application development related to the NMR relaxation time or Brownian relaxation time.